INSTRUCTION SET SUMMARY
SAHF |
Store AH register into flags |
PUSHF/PUSHFD |
Push EFLAGS onto stack |
POPF/POPFD |
Pop EFLAGS from stack |
STI |
Set interrupt flag |
CLI |
Clear the interrupt flag |
5.1.12Segment Register Instructions
The segment register instructions allow far pointers (segment addresses) to be loaded into the segment registers.
LDS |
Load far pointer using DS |
LES |
Load far pointer using ES |
LFS |
Load far pointer using FS |
LGS |
Load far pointer using GS |
LSS |
Load far pointer using SS |
5.1.13Miscellaneous Instructions
The miscellaneous instructions provide such functions as loading an effective address, executing a “no-operation,” and retrieving processor identification information.
LEA |
Load effective address |
NOP |
No operation |
UD2 |
Undefined instruction |
XLAT/XLATB |
Table lookup translation |
CPUID |
Processor Identification |
5.2X87 FPU INSTRUCTIONS
The x87 FPU instructions are executed by the processor’s x87 FPU. These instructions operate on floating-point, integer, and binary-coded decimal (BCD) operands. For more detail on x87 FPU instructions, see Chapter 8, Programming with the x87 FPU.
These instructions are divided into the following subgroups: data transfer, load constants, and FPU control instructions. The sections that follow introduce each subgroup.
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INSTRUCTION SET SUMMARY
5.2.1x87 FPU Data Transfer Instructions
The data transfer instructions move floating-point, integer, and BCD values between memory and the x87 FPU registers. They also perform conditional move operations on floating-point operands.
FLD
FST
FSTP
FILD
FIST
FISTP1
FBLD
FBSTP
FXCH FCMOVE FCMOVNE FCMOVB FCMOVBE FCMOVNB FCMOVNBE FCMOVU FCMOVNU
5.2.2x87 FPU Basic Arithmetic Instructions
The basic arithmetic instructions perform basic arithmetic operations on floating-point and integer operands.
FADD
FADDP
FIADD
FSUB
FSUBP
1. SSE3 provides an instruction FISTTP for integer conversion.
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INSTRUCTION SET SUMMARY
FISUB |
Subtract integer |
FSUBR |
Subtract floating-point reverse |
FSUBRP |
Subtract floating-point reverse and pop |
FISUBR |
Subtract integer reverse |
FMUL |
Multiply floating-point |
FMULP |
Multiply floating-point and pop |
FIMUL |
Multiply integer |
FDIV |
Divide floating-point |
FDIVP |
Divide floating-point and pop |
FIDIV |
Divide integer |
FDIVR |
Divide floating-point reverse |
FDIVRP |
Divide floating-point reverse and pop |
FIDIVR |
Divide integer reverse |
FPREM |
Partial remainder |
FPREM1 |
IEEE Partial remainder |
FABS |
Absolute value |
FCHS |
Change sign |
FRNDINT |
Round to integer |
FSCALE |
Scale by power of two |
FSQRT |
Square root |
FXTRACT |
Extract exponent and significand |
5.2.3x87 FPU Comparison Instructions
The compare instructions examine or compare floating-point or integer operands.
FCOM |
Compare floating-point |
FCOMP |
Compare floating-point and pop |
FCOMPP |
Compare floating-point and pop twice |
FUCOM |
Unordered compare floating-point |
FUCOMP |
Unordered compare floating-point and pop |
FUCOMPP |
Unordered compare floating-point and pop twice |
FICOM |
Compare integer |
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INSTRUCTION SET SUMMARY
FICOMP |
Compare integer and pop |
FCOMI |
Compare floating-point and set EFLAGS |
FUCOMI |
Unordered compare floating-point and set EFLAGS |
FCOMIP |
Compare floating-point, set EFLAGS, and pop |
FUCOMIP |
Unordered compare floating-point, set EFLAGS, and pop |
FTST |
Test floating-point (compare with 0.0) |
FXAM |
Examine floating-point |
5.2.4x87 FPU Transcendental Instructions
The transcendental instructions perform basic trigonometric and logarithmic operations on floating-point operands.
FSIN |
Sine |
FCOS |
Cosine |
FSINCOS |
Sine and cosine |
FPTAN |
Partial tangent |
FPATAN |
Partial arctangent |
F2XM1 |
2x − 1 |
FYL2X |
y log2x |
FYL2XP1 |
y log2(x+1) |
5.2.5x87 FPU Load Constants Instructions
The load constants instructions load common constants, such as π, into the x87 floating-point registers.
FLD1
FLDZ
FLDPI
FLDL2E
FLDLN2
FLDL2T
FLDLG2
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